Trees | The Magpie Gazette

The Pigeon and the Chestnut

May 16, 2017 Vita Historia

Scientists are attempting to bring the Passenger Pigeon, Ectopistes migratorius, back to life from preserved genetic material. The Passenger Pigeon once numbered up to 3 billion in North America, but by 1914 the last one had died at the Cincinnati Zoo. Scientists are also working on reviving the nearly extinct American Chestnut, Castanea dentata, which had once totaled over 3 billion trees in North America before a bark fungus accidentally imported from Asia with some Chinese Chestnuts, Castanea mollissima, destroyed almost all of the trees in the first half of the twentieth century.

Male Passenger Pigeon; digital painting by Tim Hough.

PSM V84 D563 American chestnut central maryland

American Chestnut tree in central Maryland in 1914; photo by United States Forest Service.

The loss or near loss of both these species greatly changed the ecosystem of eastern North America to the point that a visitor time traveling from the nineteenth century would be hard pressed to recognize it as the same place, never mind all the modern infrastructure of concrete, steel, and asphalt. Both species were casualties of the first stages of globalization. The Passenger Pigeons had co-existed with Native Americans for millennia, but it was the mass immigration of Europeans which eventually drove them to extinction through habitat loss and hunting on a massive scale. The American Chestnuts had no immunity to the fungus which arrived with the shipment of Chinese Chestnuts, which had developed some immunity due to having evolved with the fungus in their native habitat.

Now scientists are attempting to restore these two species once so numerous that they helped define the environment of eastern North America. Both restorations will require the expertise of geneticists, along with help from ornithologists and botanists, as appropriate. Ultimately the success of both projects will depend on the cooperation of the public by giving both species space and peace, two things that humans struggle to allow for the other beings sharing this planet. People were responsible for the demise of both the Passenger Pigeon and the American Chestnut, and with the ingenuity people are known for perhaps they can restore both species. Successful restoration will also require two things people have not often enough been known for, which are a generosity of spirit towards life and restraint of their violently destructive impulses.
― Vita

Nature American Chestnut, Asphalt, Botanists, Chinese Chestnut, Cincinnati Zoo, Concrete, Ecosystem, Environment, Europeans, Extinction, Fungus, Geneticists, Genetics, Habitat, Hunting, Immigration, Immunity, Infrastructure, Maryland, Native Americans, North America, Ornithologists, Passenger Pigeon, Scientists, Steel, Tim Hough, Trees, United States Forest Service

Careful with that Axe (at last)

September 25, 2016 Isidore Gnome

There is no time of year when you absolutely should not prune trees and shrubs, particularly when it comes to pruning for the safety of people and property or for the health of the plant. There are better and worse times, however, to paraphrase Charles Dickens from the beginning of “A Tale of Two Cities.”

Photo by Flickr user Albert Herring

Late summer and early fall is the worst time to prune, and late winter and early spring is the best time. The reason for leaving trees and shrubs alone from August through October (the timing changes depending on the first frost date where you live) is that during frost-free weather pruning encourages new growth, yet the first frost is not far off. If the plant puts out tender new growth at this time of year, a frost may damage or kill the new growth, wasting the the energy the plant just put into top growth at a time when it should be drawing its energy toward its roots in preparation for winter dormancy.

For most trees and shrubs, February through April is the best time for pruning because the plant is dormant, yet it will break dormancy soon and the flush of energy to its top growth will help heal the pruning cuts and cover them. There are exceptions to this rule, and a maple tree is one. Any maple tree produces copious sap in late winter and early spring, not just the sugar maple from which we derive maple syrup. Wounding – and yes, a pruning cut can amount to just that – a maple at that time of year results in excessive bleeding of sap, weakening it. It is better to prune a maple in the summer, when the sap does not run as freely.

Proper pruning technique is necessary in allowing a tree or shrub to to heal a cut. Do not leave stubs! A plant cannot close over a stub, and the stub eventually dies yet remains on the living plant for an inordinate time. The stub then becomes a route for insects and fungi to the interior of the plant. Pruning to the branch collar on trees and to a bud on shrubs allows the plant to seal a cut much sooner, diminishing the opportunity for pests to infest live wood.

Boston Public Garden, Massachusetts; photo by Flickr user Robert Linsdell.

Shearing is a form of pruning that makes cuts willy-nilly as far as the plant is concerned, but which to people presents the plant at a uniform shape and size, the effect of which is a matter of personal taste and opinion. At no time is shearing a boon to a plant’s health, though some plants, such as boxwood and privet, are better able to tolerate it than others. The cumulative effects of this detrimental practice are evident after several years as the plant ends up with leaves growing on its outer shell only and no leaves growing inside of that, and the outer shell becomes stiff as the branches thicken. The interior clogs over time with leaves and twigs falling from the shears, allowing fungus to grow and eventually degrade the bark. The remedy for shearing is patience to make pruning cuts by hand in the proper place as far as the plant is concerned, rather than clipping it for the sake of neatness as if a living plant was inert like hair. But as always in our culture, patience is in short supply.

– Izzy

Gardening A Tale of Two Cities, Bark, Boston Public Garden, Boxwoods, Branch Collars, Buds, Charles Dickens, Dormancy, Frost, Fungus, Maple Trees, Massachusetts, Patience, Pests, Privet, Pruning, Roots, Shearing, Shrubs, Trees

Mulch too Much

August 28, 2016 Isidore Gnome

As summer fades into fall, gardeners consider tidying their flower beds and around their trees and shrubs. Putting down new mulch can be part of this process, and it raises the question: How much mulch? Mulching two to three inches in total depth is plenty, making sure to keep the mulch from touching plant stems, and not piling up volcanoes of the stuff around trees. Any “professional” landscaping outfit or individual who does otherwise is acting out of either ignorance or the desire to sell more mulch, perhaps both.

Another consideration is whether to put down commercially produced mulch or wood chips. The term “mulch” can apply to organic or inorganic ground covers, such as pine bark, shredded hardwood, or stone. Wood chips are made from every part of a tree, and chips range in size from coarse chunks to finely ground pieces no larger than an inch. Gardeners should be careful to check the source of wood chips because they may have come from trees infested with beetles or borers, and if the chips have not been ground up finely enough or heat treated, then the insects may survive to cause further damage in new surroundings. Commercial wood mulch should not cause similar problems if the manufacturer has effectively screened it for pests, though gardeners should not apply it directly up to the foundation of a house, where it can serve as cover for termites already present in the soil.

A good rule of thumb to follow when applying mulch is not to apply it so thickly as to make it a heavy slog for the average happy garden gnome pushing a wheelbarrow.
– Izzy

Gardening Beetles, Borers, Garden Gnome, Gardeners, Ground Covers, Insects, Landscaping, Mulch, Roger Cook, Shrubs, Termites, This Old House, Trees, Volcano Mulching, Wheelbarrow, Wood Chips

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